SMAI Resistance Tube Trainer: Versatile, portable, perfect for strength and speed. The SMAI Resistance Tube Trainer is a full system kit for resistance training in any gym or home. Resistance tubes, also known as power tubes, can be used in an unlimited range of exercises and training. Train for strength in fitness programs, speed and power in boxing and martial arts programs. Use the bands to provide additional resistance in fitness & strength training, karate & martial arts, or Boxing & MMA. A